Pyridine imidazolinone compounds are members of a new class of potent herbicides that may be utilized at relatively low rates to effectively control a broad spectrum of undesirable weed species in agronomically important crops. This new class of compounds, and their use as herbicidal agents, is disclosed, respectively, in U.S. Pat. Nos: 4,638,068; 4,647,301; 4,650,514 and co-pending patent applications Ser. Nos. 850,192 filed on April 10, 1986 and 139,996 filed on Dec. 31, 1987.
The high potency of this new class of herbicides, though very advantageous for weed control at relatively low use rates, increases the possibility of injury to certain useful crop plants. The use of chemical safeners or antidotes to protect susceptible plants and plant seed from damage caused by sulfonyl urea herbicides is disclosed in U.S. Pat. No. 4,343,649.
1,8-Naphthalic anhydride may act as a safening agent for some cereal crops against injury from herbicides such as butylate, alachlor and molinate as described in U.S. Pat. Nos. 3,564,768; 3,749,566 and 3,719,466, respectively. Studies to determine the potential safening effect of 1,8-naphthalic anhydride and other safening agents on corn and sorghum against injury caused by imazaquin, a quinoline imidazolinone herbicide, have been published by M. Barrett in the Weed Science Society of America Abstracts, Volume 26, p. 77, (1986) and the North Central Weed Control Conference Proceedings, Volume 39, p. 39 (1984). In these studies, though safening was observed at low levels of herbicide applications, crop injury was still apparent when field use rates of herbicide were applied.
It is an object of this invention to provide a method to protect important crop plants from injury caused by pyridine imidazolinone herbicides by application of a chemical safener.